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For the first time, researchers have succeeded in levitating and moving arbitrarily shaped objects using acoustic (sound) waves. The researchers, from the Swiss Federal Institute of Technology (ETH) in Zurich, have already used their new-found magical powers of levitation to collide a granule of coffee and water to create instant coffee in midair — and more excitingly, a droplet of water and a piece of sodium (the explosively awesome video is embedded below). The same approach could potentially work on humans, though, without further refinements to the technology, we would probably explode or suffer catastrophic internal bleeding.

Acoustic levitation is desirable because, unlike magnetic levitation, it can be used on any object — not just materials and liquids that are magnetic. Likewise, buoyancy can be used to “levitate” some liquids, but again there are strict limitations on what liquids can be used (they must be immiscible, as with water and oil). The only limitation with acoustic levitation is that the object’s diameter must correspond to half the wavelength of the acoustic waves. As you can see, the team have no issues levitating a toothpick — something that would be impossible with both magnetic and buoyancy levitation.

Acoustic levitation has been performed before, but with very limited control of the object’s movement (video below). The breakthrough here is that researchers are able to move their acoustically levitated objects up and down, as well as side to side. The levitation effect is created by standing waves — static (standing) waves that are held in place by a reflector that bounces the same wave back upon itself, causing interference. Whereas waves usually oscillate up and down as they move through the air, a standing wave is essentially static, with the waveform forced to stay in one place. This standing wave creates a consistent upwards pressure that, if it has a strong enough amplitude (volume), can cancel out the gravity of an object placed in the standing wave.

In short, if you have enough power, you could levitate just about anything with acoustic waves — including a human. The power required would be immense, though, and at this point it isn’t clear if a human would even survive the acoustic forces. Furthermore, before you start dreaming of a portable levitation device (a jet pack!), the power requirements would probably be well beyond the capabilities of today’s lithium-ion battery packs. (Levitating a water drop requires around 160 dB).

In reality, this new development — being able to levitate multiple objects and manipulate them in a 3D space — is much more likely to find use on a smaller scale. There are many chemical and biological processes that can be disrupted by contact with a surface, and acoustic levitation is the perfect solution for such situations. Not being confined to magnetism or buoyancy as a means of levitation is also a massive boon for science: Instead of being confined to purely magnetic objects, scientists can now react anything with levitation. This might be as straight forward as reacting water and sodium, as per the video above, or it might be as complex as introducing foreign DNA into other cells using DNA transfection.

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Man I love stuff like this. It’ll be years before they apply it usefully, but that kinda leaves us something to look forward to. For now, it’s also something fantastic to look at.

Térence Vigan

What could be the possible practical domains of this ? I don’t see it for now.

Jamie MacDonald

A variation of MagLev, perhaps? I don’t know, it probably has a place in clean room style manufacture, too.

Chris Shakal

Back then, people didn’t see the practical applications of computers either.

Térence Vigan

Geez. That was a simple question. No sarcasm intended. I was thinking on a larger scale than just a laboratory, as explained in the article and really didn’t see what could be the practical solutions for this.

Daniel Harris

Hover boards and hover cars.

Térence Vigan

They said the power required for this was too much important and as it uses acoustic waves, the amplitude required could make objects reach their resonance point…or am I missing something ?

Ben Parry

power would be a requirement which is that hard part to push this into vehicles etc. However using a mini reactor,,,,

atomicjuicer

Bring me ma hoverboard! 2015 is only a year and a half away scientists!

SirGCal

Thoughts of hearing damage, acoustic structural damage, etc. runs through my mind. But aside from those fears, this is freakin sweet! The engineer in me is overly cautious though. I also wounder if it works attached to the device it’s trying to levitate instead of the other way around… curious.

Ben Parry

hearing damage would be an issue. depending on Freq. used there maybe away to at least limit some of the damaging effects.

Postulative

Love the Strauss waltz. Of course, I think anti-gravity is probably more realistic for large-scale levitation (never mind the fact that we have no idea how gravity works).

james

to make left by crating sound tid waves is not smart. in steed sound comes down and then
up on itself crating left. to say the sound is going to harm the driver meens a folty systom
its never shoud go all the way up. the in sound becomes the out sound macking the sound more like a drop of water then a tid wave. macking it safe.

Ben Parry

I think it will be sooner than people think. our research company is working on something that can do the same but with more stability with out the reflector. The ability to control orientation of the object in the field. The other side effect of what we are working on is flipping our device upside down and increasing power output it could technically be used as a levitation engine to float platforms and have control over shifting direction of engine to create all directions of movement. But you are right there are issues with reflections as waves travel great distances and using that type of pressure could cause harm. There are many other applications for this technology. think acoustic drills and more.

James Wood

I wonder if there is a way to reverse this and be able to pull something down or push it down harder? Essentially increasing gravity instead of cancelling it out. I’m thinking artificial gravity in space. Once we figure out how to make this safe for humans, we could place these generators on the ceiling and have it push the astronauts down to the floor

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